Process of concentrating ores by flotation



Patented Sept. 29, 1932 varies enrich J'GSEPH M. F. LEAIPER, OF BUFFALO,NEN YORK, ASSIGNOR TO THE BARRETT COM- ?ANY, OF NEW YORK, N. Y., AQQEPQBATION (31 NEW JERSEY PROCESS OF CONCENTRATIHG ORES BY FLO'IATIONNo Drawing.

This invention relates to the separation of minerals and theconcentration of ores by flotation processes, and is particularlydirected to such separation and concentration, whereby improved resultsare obtained, by carrying out the flotation operation with the additionto the mineral pulp or ore of a thioformaldehyde, more particularly apolymerized form of thioformaldehyde.

The thioformaldehyde, or polymerized form of thioformaldehyde, employedin the present invention can be prepared in any suitable or well-knownmanner, for example, by treating an aqueous or alcoholic solution ofhexamethylenetetramine, saturated with ammonia, with hydrogen sulfide(Berichte, vol. 19, p. 2345 (1886) by treating trimethylenetrisulfoxidewith hydriodic acid (J. f. prakt. Chemie, (2), vol. 88, pp. 50-51(1913)), by treating formalin with concentrated alkali metal sulfide toproduce trithio formaldehyde (Centralblatt, 1913, H, p. 916), and bytreating aqueous solution of sodium thiosulfate with formaldehyde andsubsequently adding hydrochloric acid (Berichte, vol. 47, pp. 256223(1914)). The present invention particularly contemplates using thethioformaldehyde, which is called thioform and prepared according tothis last method, as a flotation agent. Other methods are also known formaking thioformaldehyd-e and its polymers.

In carrying out the flotation process, the flotation agent comprisingthe thioformaldehyde may be incorporated with the ore or the mineralpulp in any suitable manner and at any suitable time which will insure asatisfactory flotation operation. For example, it may be introduced inthe free state or it may be dissolved, suspended or dispersed in anysuitable solvent or dispersing agent such as, for example, water, or oneor more of the usual flotation oils or oil mixtures, or in any suitableorganic solvent or medium, and incorporating the resulting solution,suspension or dispersion with the ore or ore pulp. While athioformaldehyde shows marked action as a flotation agent, it ordinarilypossesses insuflicient frothing qualities and is therefore generallyused to advantage in Application filed. January 16, 1928. Serial No.247,279.

conjunction with a suitable or well-known fret-hing agent, e. g., pineoil, terpineol, tar

acids, etc. lt may also sometimes be used to advantage in conjunctionwith other flotation agents.

The process of the present invention'can be carried out in any suitableapparatus, for example, those of the pneumatic type such as theCallowcell, or those where the air is incorporated with the mixture bymechanical agitation such as the Janney apparatus, or the like. 7

It is of advantage in many cases, as with certain copper ores, tosubject the pulp to the action of an amount of alkali sulticient to giveit a neutral or an alkaline reaction before subjecting it to flotationwith the aid of a thioformaldehyde. Thealkali may be caustic alkali suchas caustic soda, or an alkaline salt such as soda ash, or it may becalcium oxide or hydrate, etc.

The amount of thioformaldehyde required to be used in the flotationprocess will vary, it depending partly on the character and compositionof the ore, partly on the particular thioformaldehyde employed, andpartly on other factors. In many cases, one-sixth to one-half of a poundof the thioformaldehyde per ton of ore will be suflicient, while inother cases larger or smaller amounts than this may be required.

The invention will be further illustrated by the following specificexample, but it will be understood. that the invention is not limitedthereto. The parts are by weight.

Example: 500 parts of a copper sulfide ore (of the AnacondaCopperCompany) assaying 1.51 percent copper was ground to apulp a ballmill with 215 parts water, 0.75 parts lime, and 0.0625parts of thioforin(prepared according to Berichte, vol. i7, pages 25623 (1914) The groundpulp was diluted with water to give a mixture containing about 16percent solids and subjected to flotation in a Janney flotationapparatus. After agitating for two or three minutes, a small amount (e.g., about 0.02 parts) of pine oil was added. A satisfactory froth wasobtained. During the next 20 minutes of agitation, an amount of pine oilwas added sufficient to make a total of about 0.04: to 0.06 parts. 41parts of a con.- centrate assaying 18.61 percent copper was obtainedwhich is a recovery of 88 percent copper. The tailing assayed 0.20percent copper.

It will thus be noted that the present invention contemplates theutilization of a thioformaldehyde as a flotation agent in the separationof minerals and the concentration of ores; that it may be incorporatedwith the ore or mineral pulp in any well-known or suitable manner; andthat it may be employed in the free state or in solution, suspension ordispersion in any suitable solvent or medium. 7

It will be understood that the present invention is applicable to thetreatment of various kinds of mineral mixtures, both natural andartificial, which are amenable to concentration by flotation processes.

I claim:

1. In the process effecting the concentration of minerals by flotation,the improvement which comprises adding a thioiormaldehyde to the mineralpulp and subjecting the resulting mixture to a froth flotationoperation.

2. A method of effecting the concentration of minerals by flotationwhich comprises incorporating thioform with the mineral pulp andsubjecting the mixture to a froth flotation operation.

3. In efiecting the concentration of miner-- als by flotation, theprocess which comprises subjecting a sulfide ore in the form of apulp toa froth flotation operation in the presence of from aboutone-sixth toabout one-half pound of a thioformaldehyde per ton of ore treated.

1. In effecting the concentration of miner-- als by flotation, theprocess which comprises: subjecting a copper sulfide ore in the form ofa pulprto a froth flotation operation in thepresence of from aboutone-sixth to about one-half pound of thioform per ton of ore treated.

5. In efiecting the concentration of miner als by flotation, the processwhich comprises subjecting a copper sulfide ore in the form of a pulp toa froth flotation operation in the presence about one-fourth pound of athioformaldehyde prepared by treating sodiumthiosulfate in the presenceof formaldehyde with hydrochloric acid per ton of ore treated- Intestimony whereof I affix my signature.

JOSEPH M. F. LEAPER.

